JP2748271B2 - V-type engine camshaft drive - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a camshaft driving device for a V-type engine, and more particularly to a first camshaft sprocket disposed on a first cylinder head on a protruding bank side and a reverse bank side. And a second camshaft sprocket disposed on a second cylinder head of the V-type engine connected by a single timing chain.

[Conventional technology]

The internal combustion engine includes an in-line engine, an opposed engine, a V-type engine, and the like, depending on the arrangement of the cylinders. In this V-type engine, a first bank cylinder and a second bank cylinder are disposed in a cylinder block in a V-shape at a predetermined angle.

As shown in FIG. 4, a camshaft driving device for a conventional V-type engine includes a first cylinder head 108 on the projecting bank side and a second cylinder head 110 on the reverse bank side of the V-type engine 102, respectively. 1, the second camshaft 118,
The first and second camshafts 118 and 122 are fixedly provided on one end sides of the first and second camshafts 118 and 122, respectively, in the form of flat plates.

Furthermore, as other V-type engines,
As disclosed in Japanese Patent Publication No. 308, a camshaft is disposed on each of the cylinder heads of the left and right banks, and a cam drive transmission line for driving the camshaft is provided on one end surface of the cylinder block in the crankshaft direction for each bank. V is provided so that each camshaft is driven by a crankshaft via these cam drive transmission lines.
A water pump is disposed in the center of the bank above the crankshaft on one end surface of the cylinder block, and is disposed so as to avoid a bearing housing that rotatably holds an impeller rotating shaft of the water pump, and a crankshaft. Some were arranged so as to overlap the cam drive transmission line in the direction.

[Problems to be solved by the invention]

By the way, in a conventional camshaft driving device of a V-type engine, a first camshaft sprocket and a second camshaft sprocket fixed to one end sides of a first camshaft and a second camshaft are formed in a flat plate shape. Was done.

As a result, when installing the timing chain, the second camshaft sprocket on the reverse bank side and the first camshaft sprocket fixed to one end of the first camshaft on the protruding bank side are positioned on the same plane. To
That is, the second camshaft sprocket must be fixed outwardly so as to protrude outwardly, so that the overall length of the V-type engine is increased, resulting in an increase in the size of the V-type engine. However, there is a disadvantage that the weight is increased, which is disadvantageous in practical use.

[Object of the invention]

Accordingly, an object of the present invention is to reduce the overall length of the V-type engine by reducing the length of the V-type engine by bringing the rim portion of the first camshaft sprocket meshing with the timing chain closer to the first cylinder head side in order to eliminate the above-mentioned disadvantage. It is an object of the present invention to provide a camshaft driving device for a V-type engine that can reduce the size and weight of the type engine.

[Means for solving the problem]

In order to achieve this object, the present invention relates to a first engine disposed on a first cylinder head on a projecting bank side of a V-type engine.
In a camshaft driving device for a V-type engine in which a camshaft sprocket and a second camshaft sprocket disposed on a second cylinder head on the opposite bank side are connected by a single timing chain, the first shaft meshing with the timing chain is provided. A bent portion is formed at least at a substantially intermediate portion of the first camshaft sprocket so that the rim portion of the camshaft sprocket is close to the first cylinder head side.

[Action]

With the above-described configuration, the first camshaft sprocket whose rim portion is close to the first cylinder head side is attached to the first camshaft on the protruding bank side. There is no need to protrude the two-camshaft sprocket outward, thereby reducing the overall length of the V-type engine and reducing the size and weight of the V-type engine.

〔Example〕

Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings.

1 to 3 show an embodiment of the present invention. 1 to 3, reference numeral 2 denotes a V-type engine, (hereinafter referred to as an engine) 4 is a cylinder block, 6 is an oil pan, 8 is a first cylinder head on the protruding bank side, and 10 is a second cylinder head on the reverse bank side.
It is a cylinder head. The engine 2 has a V-shaped cylinder block 4 in which first and second bank cylinders (not shown) are disposed. An oil pan 6 is fixed to the lower opening 4a of the cylinder block 4, and the first and second cylinder heads 8 are provided at two upper openings 4b and 4c, respectively.
A first and a second cylinder head covers 12 and 14 are fixedly mounted on the upper surfaces of the first and second cylinder heads 8 and 10, respectively.

A first camshaft 18 is provided in the first valve chamber 16 on the first cylinder head 8 side, and a second camshaft 22 is provided in the second valve chamber 20 on the second cylinder head 10 side.
Are arranged.

As shown in FIGS. 1 and 2, a first camshaft sprocket 24 is provided at one end of the first and second camshafts 18 and 22.
And a second camshaft sprocket 26 are fixedly provided by bolts 28.

The first camshaft sprocket 24 and the second camshaft sprocket 26 are connected by a timing chain 32 to which an appropriate tension is applied by a tension adjusting device 30. The timing chain 32 transmits the driving force of a crankshaft sprocket 36 fixed to the crankshaft 34 to the first and second camshaft sprockets 24 and 26.
To communicate.

Further, the first camshaft sprocket 24 is
A bent portion 38 is formed at a substantially intermediate portion between the center and the outer peripheral portion of the first camshaft sprocket 24 so as to approach the cylinder head 8 side, and the rim portion 24a meshed with the timing chain 32 is provided on the first cylinder head side. Is provided in the vicinity. The second camshaft sprocket 26 includes:
As shown in FIG. 2, for example, it is formed in a flat plate shape.

Reference numeral 40 denotes a first cam of the first camshaft 18, and reference numeral 42 denotes a second cam of the second camshaft 22.

 Next, the operation will be described.

The first cylinder arranged on the first cylinder head 8 of the engine 2
A first camshaft sprocket 24 is adhered to the camshaft 18 so that the rim portion 24a comes close to the first cylinder head 8, and a second camshaft sprocket is attached to a second camshaft 22 disposed on the second cylinder head 10.
Attach 26.

And the first and second camshaft sprockets 2
The first and second camshaft sprockets 24 and 26 and the crankshaft sprocket 36 are connected by a timing chain 32.

Thus, the overall length of the engine 2 can be shortened, and the size and weight of the engine 2 can be reduced, which is practically advantageous.

Also, since the first camshaft sprocket 24 having the bent portion 38 formed at a substantially intermediate portion between the center and the outer peripheral portion of the first camshaft sprocket 24 is attached to one end of the first camshaft 18, the first camshaft Unnecessary lengths of the shaft 18 and the crankshaft 36 can be omitted, and the rigidity of the crankshaft 36 can be improved.

Further, by reducing the size and weight of the engine 2, it is possible to improve the degree of freedom in mounting the engine 2 in an engine room when the engine 2 is mounted on a vehicle (not shown).

Note that the present invention is not limited to the above-described embodiment, and various application modifications are possible.

For example, in the embodiment of the present invention, the second camshaft sprocket formed by an annular flat sprocket is fixedly provided on one end side of the second camshaft.
When the interbank space is large, the first camshaft sprocket rim is overlapped with the second camshaft sprocket rim by the first
A second bend formed in the opposite direction to the camshaft sprocket
It is also possible to use camshaft sprockets.

[Effects of the Invention] As described above in detail, according to the present invention, at least substantially the middle of the first camshaft sprocket so that the rim portion of the first camshaft sprocket meshing with the timing chain approaches the first cylinder head side. By forming a bent portion in the portion, the overall length of the V-type engine can be reduced, and the V-type engine can be reduced in size and weight, which is practically advantageous. In addition, the first camshaft sprocket is bent so as to be close to the first cylinder head side, so that a timing chain connecting the first camshaft sprocket and the second camshaft sprocket is formed on a side portion of a V-type engine. , The length of the crankshaft in the cylinder block can be shortened, and the rigidity of the crankshaft can be improved.

[Brief description of the drawings]

1 to 3 show an embodiment of the present invention. FIG. 1 is a schematic enlarged sectional view of a projecting bank-side first cylinder head of a V-type engine, and FIG. 2 is a reverse bank-side second cylinder head of a V-type engine. FIG. 3 is a schematic side view of a V-type engine. FIG. 4 is a schematic sectional explanatory view of a V-type engine showing a camshaft driving device of a conventional V-type engine. In the drawing, 2 is a V-type engine, 4 is a cylinder block, 6 is an oil pan, 8 is a first bank head on the protruding bank side, 10 is a second cylinder head on the reverse bank side, 12 is a first cylinder head cover, and 14 is a first cylinder head cover. Cylinder head cover,
16 is a first valve chamber, 18 is a first camshaft, 20 is a second valve chamber, 22 is a second camshaft, 24 is a first camshaft sprocket, 26 is a second camshaft sprocket, 28 is a bolt, 30 is a tension adjustment device, 32 is a timing chain, 34
Is a crankshaft, 36 is a crankshaft sprocket, 38 is a bent portion, 40 is a first cam, and 42 is a second cam.

Claims (1)

(57) [Claims] A first camshaft sprocket disposed on a first cylinder head on a protruding bank side of a V-type engine and a second camshaft sprocket disposed on a second cylinder head on a reverse bank side have one timing. In a camshaft drive device of a V-type engine connected by a chain, at least a substantially intermediate portion of the first camshaft sprocket such that a rim portion of the first camshaft sprocket meshing with the timing chain is brought closer to a first cylinder head side. A camshaft drive device for a V-type engine, wherein a bent portion is formed at a portion.